Distribution Of Glucagon Research Articles

Microscopical Study of Pancreatic Tissue of Babirusa (Babyrousa babyrussa) Using Conventional and Immunohistochemical Methods

This study utilized conventional and immunohistochemical methods, to describe the morphology and distribution of glucagon and insulin cells in the pancreas of adult male babirusa (Babyrousa babyrussa). The results of research showed that the endocrine portion (Langerhans islet) spread evenly on the acinar portion of pancreas. Observation using immunohistochemical method showed that glucagon cells were distributed on the perifer, whereas insulin cells in the center of the Langerhans islet of pancreas. In general, the number of insulin cells was higher than glucagon cells. It is interesting to note, in the pancreas babirusa also found that neonatal elements similar to the Langerhans islet, but have larger sizes (ranging between 200 -700 mm). The picture is similar to the large Langerhans islet was reported in ruminant. These cells give a negative reaction to insulin and glucagon antisera.

Immunohistochemical Investigation of F344/N Rat Islet Cell Tumors from National Toxicology Program Studies

In this study, we have investigated the immunoexpression of peptide hormones and mediators associated with human islet cell tumors in a group of proliferative islet cell lesions in F344 rats including islet cell hyperplasias, adenomas, and carcinomas, as defined by conventional histopathologic criteria. All proliferative islets expressed synaptophysin, although decreased expression intensity was observed in hyperplasias and adenomas. Most of the proliferative lesions expressed insulin, which generally decreased as lesions progressed toward malignancy. The distribution of glucagon, somatostatin, and gastrin-expressing cells was altered in proliferative islet lesions but did not comprise a large proportion of cells. Islet cell tumors were associated with increased nuclear expression of cyclin-dependent kinase 4 as well as increased proliferating cell nuclear antigen and decreased β-catenin expression. c-Myelocytomatosis oncogene expression was variable. This is the first study to describe the immunophenotype of islet cell tumors in the F344 rat and to show that islet cell tumors in the F344 rat exhibit similarities in protein expression to the human counterpart.

The ontogeny and distribution of glucagon- and pancreatic polypeptide-immunoreactive cells in the gastrointestinal tract of the chicken

The times of first appearance and the distribution of APP- and glucagon-immunoreactive cells have been established in the embryonic chick gut between 11 days of incubation and hatching. These immunoreactive cell types appeared for the first time at 13 days of incubation, APP-immunoreactive cells in the duodenum and upper ileum and glucagon-immunoreactive cells in the proventriculus and duodenum. At 14 days, APP-immunoreactive cells were detected in the proventriculus and lower ileum and glucagon-immunoreactive cells in the pyloric region, upper and lower ileum. Thereafter both APP- and glucagon-immunoreactive cells increased in frequency until the numbers at hatching were approximated, APP-immunoreactive cells at 19 days and glucagon immunoreactive cells at 17 1/2 days of incubation. No APP- or glucagon-immunoreactive cells were found in the gizzard, caecum or rectum at any of the selected stages examined. When these types of endocrine cells first appeared, the surface epithelium of the gastrointestinal tract was relatively undifferentiated. A few glands were present in the proventriculus only, at this stage. Thereafter immunoreactive cells of both types were found in the glandular epithelium of the proventriculus, pyloric region and small intestine soon after morphogenesis had begun.

Immunocytochemical and ultrastructural characterization of coexistence of pancreatic polypeptide and glucagon-like immunoreactivity in the pancreatic endocrine cells of Sparus auratus L. (Teleostei)

Coexistence of pancreatic polypeptide (PP)- and glucagon-like immunoreactivity was demonstrated in the pancreatic endocrine cells of the teleost fish Sparus auratus. An immunofluorescence double-staining method revealed coexistence of glucagon- and PP-like immunoreactivity in endocrine cells of small and intermediate islets. In contrast to small islets, the intermediate ones also contained a variable number of glucagon-immunoreactive cells next to cells having both immunoreactivities. Coexistence of both immunoreactivities could not be observed in endocrine cells of the principal islet, whereas many cells containing glucagon and a few cells containing PP immunoreactivity were found. By an immunogold double-staining method the precise ultrastructural location of each immunoreactivity could be demonstrated. Again, cells containing glucagon- and/or PP-like immunoreactivity were found. Although, only two different types of granules were observed, four distinct cell types could be distinguished. Based on this granule morphology two cell types showing coexistence were found: one cell type, only present in the small islets, showing a different distribution of glucagon and PP immunoreactivity within the granules (predominantly in the center and periphery, respectively) and another cell type with larger granule cores, present in small as well as intermediate islets, having a mixed distribution of both immunoreactivities.

Sustained Feeding or Fasting Affects Levels of Glucagon (IRG) in Porcine Plasma, Gut and Pancreas

Arterial glucagon levels are elevated in fed pancreatectomised pigs and the source was sought by measuring the hormone in arterial, portal, hepatic and renal venous blood, and in gut tissues. Pigs which were starved for 48 hours (basal) were compared with sham operated or pancreatectomised pigs which were fed or starved for 7 days post operatively. Feeding of sham operated pigs caused a uniform increase in IRG 3485, while starvation resulted in a decreased portal IRG 7000. Pancreatectomy was associated with a uniform decrease in portal IRG 3485 and increase of IRG 7000 regardless of nutritional status. Hepatic and renal extraction of 23-26% was noted in fed animals (IRG 3485 in sham operated; IRG 7000 in pancreatectomised). In all starved pigs, hepatic and renal extraction were reduced to zero. The gastric and caecal mucosa and the pancreas contained most of IRG 3485. Gastric and caecal levels were increased after feeding of either group of animals, while fasting caused a marked increase in pancreatic IRG 3485 and a decrease in ileal IRG 7000. These studies demonstrate a direct effect of sustained nutritional status upon the distribution of glucagon in plasma and gastro intestinal tissues.

Neuroendocrine cells within colorectal tumours induced by dimethylhydrazine

Colorectal adenocarcinomas were induced in male Wistar rats, by weekly subcutaneous administration of 1,2-dimethylhydrazine, classified according to the degree of differentiation and submitted to immunocytochemistry for the peptides cholecystokinin (CCK), gastrin, gastric inhibitory polypeptide (GIP), glucagon, neurotensin, pancreatic polypeptide (PP), peptide YY (PYY), somatostatin and vasoactive intestinal polypeptide (VIP) and the biogenic monoamine 5-hydroxytryptamine. Well- or moderately well-differentiated adenocarcinomas comprised 46% of the tumour population, only 4% were poorly-differentiated adenocarcinomas, and the remaining 50% possessed a mixture of these two morphologies. Glucagon, PYY and 5-hydroxytryptamine immunoreactive cells were frequently observed within well- or moderately well-differentiated tumours and within such regions of tumours possessing a mixed morphological pattern. The tumours contained no cells immunoreactive for any of the peptides not normally located within the colorectum, nor did they contain cells immunoreactive for somatostatin and VIP, although known positive controls did stain. Poorly-differentiated tumours and portions of tumours of mixed type, were consistently negative. 5-hydroxytryptamine was the most frequently located of the three antigens, being detected in 87% of the moderately well-differentiated tumours and 32% of the tumours with mixed morphologies. 11% of moderately well-differentiated tumours possessed 5-hydroxytryptamine positive cells in such profusion that they contributed significantly to the tumour mass. The distribution of glucagon- and PYY-immunoreactive cells was similar, although they occurred with a lower frequency, presumably corresponding to their lower numbers within the normal colorectal mucosa. Additionally, these two peptide immunoreactivities were colocalized in the majority of cells, although some cells contained only one antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Electron microscopic immunocytochemical localization of glucagon and pancreatic polypeptide in rat pancreas: characterization of a population of islet cells containing both peptides.

The distribution of glucagon and pancreatic polypeptide was studied immunocytochemically in rat pancreas at both light and electron microscopic levels. My earlier observation that these two peptides are distributed in three cell types--cells containing glucagon, cells containing pancreatic polypeptide, and cells containing both--was confirmed at the electron microscopic level. In the glucagon-pancreatic polypeptide cells, the immunoreactivities of the two peptides were present in the same secretion granules. In addition, these glucagon and pancreatic polypeptide-containing granules were morphologically distinct from glucagon granules but similar to pancreatic polypeptide granules and somatostatin granules.

Distribution of glucagon and glicentin immunoreactive cells in the small and large intestine

Distribution of glucagon and glicentin immunoreactive cells in the small and large intestine

Immunohistochemical identification and localization of pancreatic polypeptide cells in the pancreas and gastrointestinal tract of the human fetus and adult man.

Pancreatic polypeptide (PP)-containing cells were detected by using anti-bovine PP (BPP) serum in the pancreas and gastrointestinal tract of human fetuses, premature infants and in the pancreas, antrum and jejunum of adult man obtained by biopsy from patients with normal gastroduodenal endoscopy. The localization was established by studying the distribution of PP cells in comparison to the distribution of glucagon-, somatostatin- and insulin cells. The first PP cells are seen in the pancreas at 10 weeks of gestation. They are located preferentially in the lower part of the head of the pancreas. The specificity of immunocytological reaction was ascertained by the inhibition of the reaction by bovine pancreatic polypeptide, glucagon and insulin did not modify the immunocytological reaction.

Relationship of glucagon-somatostatin and gastrin-somatostatin cells in the stomach of the monkey

The stomach of the monkey Tupaia belangeri was investigated by serial sections utilizing the indirect immunoperoxidase reaction to demonstrate the distribution of glucagon, gastrin and somatostatin immunoreactive cells. A striking topographical distribution was found. Glucagon and somatostatin immunoreactive cells were located in the upper parts, whereas gastrin and somatostatin immunoreactive cells were situated in the lower parts of the stomach. The remaining regions of the stomach did not contain cells immunoreactive to the antisera applied. Similarly, the ultrastructural study revealed the same distribution of endocrine cell types identified as A-cells, D-cells, and G-cells. Thus, there may be a glucagon-somatostatin area in the upper part and a gastrin-somatostatin endocrine surface in the lower part of the stomach. This spatial relationship of the endocrine cells suggests a functional cell interaction between glucagon and somatostatin cells in the cranial stomach and between gastrin and somatostatin in the caudal parts of the stomach.